Known elastomers for cushioning shock include polyurethane elastomers and ethylene vinyl acetate polymers. U.S. Pat. No. 4,346,205 shows a typical example of a polyurethane. It has a low hardness and low compression set but a slow recovery after compression which makes it less than ideal for use as an insert in footwear.
It is therefore an object of the invention to provide a non-polyurethane elastomer which is highly suitable for use in making inserts in footwear.